BOSTON — Boston Marathon bombing suspect Dzhokhar Tsarnaev won’t be indicted within the 30-day period prescribed under the Federal Speedy Trial Act but prosecutors said Friday they would ask for more time.

Sunday marks 30 days since Tsarnaev was arrested following the April 15 twin bombing that killed three people and injured more than 260.

U.S. Attorney Carmen Ortiz’s office did not specify the exception under which they would seek more time but those available to prosecutors include delays related to the defendant’s physical capacity. Tsarnaev remains in a prison hospital after being badly wounded in a gunbattle with police.

Earlier Friday, a judge denied a request from Tsarnaev’s attorneys that they be allowed to take periodic photos of the 19-year-old to document “his evolving mental and physical state” and whether his statements to authorities after his arrest were made voluntarily.

Tsarnaev’s lawyers could be trying to argue that statements he made to authorities after his arrest on April 19 were not voluntary because of his poor physical condition. Defense attorney Miriam Conrad declined to comment.

The motion from Tsarnaev’s lawyers remained sealed Friday. But the ruling by U.S. Magistrate Judge Marianne Bowler included excerpts from the defense filing, which suggest Tsarnaev’s lawyers may want to use the photos to argue for a lighter sentence.

Tsarnaev, 19, is charged with using a weapon of mass destruction in the April 15 bombings. He could face the death penalty if convicted.

Bowler said Tsarnaev’s lawyers asked if they could regularly take their own photos of Tsarnaev.

Bowler found Tsarnaev’s lawyers could not take their own photos, saying the Fort Devens prison where Tsarnaev is housed has a policy against visitors bringing cameras. The Bureau of Prisons could take photos of Tsarnaev with his lawyers present, but those pictures would have to be shared with prosecutors, Bowler said.